The minimum requirement of a nano-gripper is the tips of its arms such that their size is equal to or smaller than the size of objects to be handled. To handle nano-objects such as DNA's in particular with a nano-gripper, the tips of its arms have to be as minute as 50 nanometers or less. Such a nano-gripper is made by attaching carbon nano-tubes to the tips of probes for an interatomic-force microscope. Nano-grippers are also produced by electron-beam deposition and electric-field vapor-deposition methods. A known nano-gripper is twin probes with integrated actuators, which are made of silicon nano-wire produced by the electron-beam deposition or electric-field vapor-deposition method, or the anisotropy etching of silicon.
The nano-grippers currently in use and their production methods have the problems below.
(i) Arms for current nano-grippers made of carbon nanotubes or silicon nanowire or produced by the electron-beam deposition or electric-field vapor-deposition method are pillar-like, or post-like, slim members. Such a member is flexible in proportion to the 3rd power of its length (it bends easily under force applied to its tip). If such a member has a circular cross section, it is flexible in inverse proportion to the 4th power of its diameter. In other words, slim members such as nanowire have very small strength against bending force. DNA's and particles on VLSI boards are minute and have to be handled in a solution to prevent them from scattering or drying. While the tips of arms of a current nano-gripper are dipped in such a solution, its probe structure is affected by the viscosity of the solution.
(ii) According to the electron-beam deposition or electric-field vapor-deposition method, arms in conformity with individual specifications are produced one by one in a vacuum device; therefore, highly controllable arms can be produced, but their industrial mass production is difficult. In addition, because a nano-gripper with an actuator of the order of magnitude of nanometers cannot be produced by the electron-beam deposition method or the like, it is difficult to control the gaps between the tips of arms of nano-grippers minutely.
(iii) The production of twin probes with integrated actuators requires the steps of making a special composite board unavailable on the market and the extremely precise management of etching conditions; therefore, the production process of such twin proves with integrated actuators is too complex. If the management of etching conditions is inadequate, mass production with high repeatability and uniformity of such twin probes with integrated actuators is impossible.
(iv) Although the tips of arms of a nano-gripper can be sharpened with high precision of the order of magnitude of nanometers with high-precision lithography, such lithography is costly.
In view of the above, an object of the present invention is to provide a nano-gripper which has, on its arms' tips, protrusions with a radius of curvature of the order of magnitude of nanometers formed without using high-precision lithography. Even when the nano-gripper is used to handle DNA's, etc. in a solution, its probe structure is not affected; therefore, the operator can control the gap between the protrusions easily and precisely. The nano-gripper can be mass produced easily, inexpensively. Another object of the present invention is to provide the process of producing the nano-gripper.